The invention relates to a delivery for a sheet-processing machine, having a frame, grippers which, during operation, revolve along a gripper path within the frame, and grip a respective sheet at a location on the gripper path and drag the sheet along sections of the gripper path in a transport direction, a first switching element, by which a first end of a first one of the sections of the gripper path, which is disposed downline with respect to the transport direction, is definable, and a second switching element, by which a second end of a second one of the sections of the gripper path, which is disposed downline with respect to the end of the first section, is definable.
A delivery of the aforementioned type is disclosed in the published Japanese Patent Document JP Sho 64-294 B2. The first switching element provided therein defines a first end of a first section of the gripper path, disposed downline with respect to the transport direction, inasmuch as, in the switching position thereof at this end, it opens grippers which drag a sheet along this first section of the gripper path specifically in order to release the sheets, which are dragged along this first section of the gripper path, in order to form a delivery pile.
The second switching element of the heretofore known delivery is located downline from the first switching element, with respect to the transport direction, and defines a second end of a second section of the gripper path, disposed downline from the first end of the first section of the gripper path, disposed downline, inasmuch as, in an ineffective position of the first switching element, it releases the sheets, in this case, dragged by the grippers as far as the aforementioned second end while opening the grippers at this second end, so that the sheets released thereat shoot out beyond the delivery pile and, in the heretofore known delivery, with guidance by sheet guide brackets, are supplied to a deposit container which is located downline from the delivery pile and into which, in this way, proof sheets or rejects are led.
The second switching element of the heretofore known delivery can be adjusted to different switching positions along the gripper path within a specific region of the latter in order to be able to adapt the point of release, for example, of proof sheets, to the machine speed. However, this region is located in a rectilinear section of the gripper path. One reason for this is apparent in that the physical position of the sheets released with the aid of the second switching element is supposed to be maintained independently of the location of the release thereof, apart from a change in location.
However, as implemented in the heretofore known delivery, this necessarily makes it possible for a curved region, which deflects the gripper path and through which the grippers pass on the return path thereof to the location for gripping further sheets, to be provided only at a specific minimum distance from the adjustment region of the second switching element. This has an effect upon the overall length of the heretofore known delivery inasmuch as the deflection region of the gripper path is located considerably farther downline than the side face of the delivery pile which is directed downwardly.
It is accordingly an object of the invention to provide a delivery for a sheet-processing machine of the general type described in the introduction hereto, which is configured so that the extent thereof required downline from the delivery pile can be kept as short as possible.
With the foregoing and other objects in view, there is provided, in accordance with the invention, in a sheet-processing machine, a delivery comprising a frame, grippers revolvable, during operation, along a gripper path within the frame, the grippers serving for seizing a respective one of the sheets at a location on the gripper path and for dragging the sheet along sections of the gripper path in a transport direction, a first switching element, by which a first end of a first one of the sections of the gripper path, disposed downline with respect to the transport direction, is definable, and a second switching element, by which a second end of a second section of the gripper path, disposed downline with respect to the end of the first section, is definable, the first switching element being disposed on the frame, and the second switching element being disposed on a guide part fixed to the frame, and serving for determining a section of a course of the gripper path.
In accordance with another feature of the invention, the switching elements are adjustable between a respective switching position and a respective ineffective position, and the reverse.
In accordance with a further feature of the invention, one of the two switching elements is in the switching position thereof when the other of the two switching elements is adjusted into the ineffective position thereof, and the reverse.
In accordance with an added feature of the invention, the first switching element is adjustable from the respective switching position thereof into the respective ineffective position by being liftable with respect to the gripper path, and the second switching element being adjustable from the respective switching position into the respective ineffective position by being movable laterally off the gripper path.
In accordance with an additional feature of the invention, the delivery includes a coupling mechanism attached to the frame, the coupling mechanism having a coupler forming the first switching element.
In accordance with yet another feature of the invention, the coupling mechanism includes a first rocker pivotable about a locally fixed, first geometric axis, and a second rocker pivotable about a second geometric axis and having a position that is adjustable.
In accordance with yet a further feature of the invention, the second geometric axis is adjustable to geometric locations on a circular path.
In accordance with yet an added feature of the invention, the delivery includes a pivot arm attached to the guide part and carrying the second switching element.
In accordance with yet an additional feature of the invention, the switching elements are connected kinematically to one another.
In accordance with still another feature of the invention, the delivery includes a spring for biasing the second switching element with an actuating force in a direction towards the switching position thereof, and a control cam adjustable while the first switching element is being adjusted, and by which the second switching element is adjustable from the switching position thereof into the ineffective position thereof counter to the actuating force and, under the action of the actuating force, is adjustable from the ineffective position thereof into the switching position thereof.
In accordance with still a further feature of the invention, the frame has a side wall.
In accordance with a concomitant feature of the invention, the guide part is a deflection rail arrangement.
Thus, the object of the invention is achieved by disposing the first switching element on the frame, and disposing the second switching element on a guide part that is fixed to the frame and that determines a section of the course of the gripper path.
This construction ensures, on the one hand, that the release of the sheets by the revolving grippers, which can be triggered by the first switching element, always takes place at the end of a first section of the gripper path, which can be matched with or adjusted to the formation of the delivery pile, and it is thereby possible, on the other hand, for the end of the second section of the gripper path, i.e., the location at which the corresponding release of the sheets, which can be triggered by the second switching element, takes place, in particular with respect to a deflection region of the gripper path, which follows the end of this second section, to always be at one and the same location. The release of the sheets, which can be triggered by the second switching element, can thus be provided in particular at a location which lies in the aforementioned deflection region without any change resulting in the physical position of the sheets at the instant at which they are released, in case of a displacement, required, in particular, to retension chains normally used to transport the grippers, of the deflection region, besides a change in the release location. Maintaining the aforementioned physical position is an important precondition for proper transfer of a sheet released by the grippers to a transport device which, for example, includes revolving belts which brake the sheets, and by which the sheets are supplied to a deposit for proof sheets or rejects which is placed downline from the delivery pile with respect to the transport direction. In addition to the intended shortening of an extent of the delivery provided beyond the delivery pile, the configuration of the delivery according to the invention also satisfies the aforementioned precondition.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a delivery for a sheet-processing machine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: